A storage apparatus compatible with a small computer system interface (SCSI) exchanges data in units of data blocks of, for example, 512 bytes.
In recent years, there are storage apparatuses such as a solid state drive (SSD) that use a flash memory as a recording medium. With a NAND flash memory, data is read/written in units called “pages” of, for example, 8 kilobytes.
Data being held in a flash memory is by nature prone to error. Therefore an error correcting code (ECC) is added. A set of data stored in a flash memory and an ECC with respect to the data is referred to as code word (CW) (PTL 1 and PTL 2).